1. Field of the Invention
The present invention relates to coupling devices for connecting electrical conductors, and in particular to an apparatus and method for providing and maintaining a blast hardened electrical connection between electrical conductors.
2. The Prior Art
Coupling devices for connecting electrical conductors are well known and commonly used in numerous applications ranging from the connection of very tiny electronic circuits to physically large, high voltage electrical transmission lines. Typical coupling devices include such things as metallic sleeves which are slipped over and secured to the butted ends of the conductors, split bolt connectors, and devices having two or more clamps which are electrically connected, each clamp receiving and securing the end of a conductor.
Electrical connectors are generally designed to accomplish two goals. First, a connector is designed to secure the conductors in electrical contact during all expected operating conditions. The second goal is to protect the conducting surfaces of the conductor from exposure to undesirable conditions in the surrounding environment. In order to accomplish these goals the connectors generally secure the conductors in rigid, fixed position with respect to each other so that, even in the case of jarring or movement of the connector or the conductor, the electrical connection will be maintained. Exposure is generally prevented by providing an outer covering which may be waterproof, dust proof, or which may provide other types of protection as necessary in light of the expected operating conditions.
Although devices and methods such as those described above have been satisfactory for their intended applications under normal operating conditions, such devices and methods have generally been considered "soft" for security purposes, and have been unacceptable for applications involving operation under extreme conditions which may be created by an enemy attack or a natural disaster. "Hardness" (or "softness") is a military term to denote the system's vulnerability to destruction under attack. The harder a system is, the less vulnerable to destruction it is.
The hardness of many electrical systems requiring connector devices may be measured by such criteria as their ability to withstand substantial shock, as in the case of a powerful explosion occurring very near to the system.
When electrical connectors are utilized in systems which are exposed to conditions such as those produced by nearby explosions, the connectors become exposed to extreme forces which have such destructive power that the connectors may simply be destroyed or made unable to properly function. This is particularly true in the case of electrical connectors which are utilized for connecting conductors positioned upon or beneath the surface of the earth.
Electrical connectors are often necessary in these types of systems in order to secure and maintain electrical contact between conductors which form portions of underground or surface antennas and antenna arrays. Particular embodiments of such systems are described in the copending patent applications of Ferril A. Losee, U.S. Ser. Nos. 393,043 and 393,044, each filed on June 23, 1982, and entitled, respectively, "Wireless Communication System Using Current Formed Underground Vertical Plane Polarized Antennas" and "Low Profile Wireless Communication System and Method", both of which are incorporated herein by reference.
When an intense explosion occurs, such as that produced by a nuclear weapon, it produces shock waves which travel throughout the surrounding environment, including the air, earth, and water. As the shock waves travel through the earth, they produce a substantial displacement of the ground, which responds in a manner similar to fluid materials. Thus, the ground is actually caused to rise and fall in a wave action, with the wave amplitude being several inches or even feet depending upon the physical structure and composition of the ground and the size and location of the force which initiated the shock waves.
Conventional electrical connectors are simply not adequate for use in underground and surface communication systems which must withstand the extreme forces produced by such traveling shock waves. Under these conditions, the securely fastened and rigidly held conductors often pull free or break, since they have no way to accommodate the forces which are experienced. Thus, even though a powerful explosion may be centered some distance from the underground communication system, the resulting shock waves may likely result in breakage or separation of the conventional, tightly secured electrical connection. These types of conditions can also be associated with earthquakes and other similar natural phenomena, also with similar, unacceptable results.
It is extremely important that such communication systems and the like be constructed so as to be able to withstand the excessive forces which may occur during natural disasters or as a result of explosive shock. It is under these circumstances when the proper functioning of communication systems and other electronic equipment requiring electrical connectors is of utmost importance not only for local emergency purposes, but also to possibly preserve the national security. Nevertheless, electrical connectors capable of properly functioning under such extreme circumstances have not been provided and thus, the problem continues to exist.
As is apparent from the above discussion, what is needed in the art is a device and method for securing and maintaining electrical conductors in electrical contact, even during the extreme operating conditions which may occur during natural disasters or as a result of enemy attack. A further improvement in the art would be to provide such a blast hardened system which additionally provides for ease of installation and interconnection of the conductors to be electrically connected. Such a device and method is disclosed and claimed herein.